Means for determining the wear of diamond-pointed tools and the like



Dec. 17, 1929". KOEBEL r AL 1,739,553

MEANS FOR DETERMINING THE WEAR OF DIAMOND POINTED TOOLS AND THE LI KE Filed May 3, 1924 aha/ (27. xe/

- tool. Tools of this character Patented Dec. 1-7, 1929 UNITED STATES PATENT OFFICE FRANK E. KOEBEL,

Application filed May 3,

This invention relates to diamond-pointed cutting, grinding and dressing tools. In these toolsa diamond is rigidly embedded in a recess at one end of the body of the are expensive, and the use thereof is largely confined to skilled workmen. It is therefore very desirable that these valuable tools be conserved, and that they be used by such men only when operating at highest eificiency. In present practice it is left to the workmen themselves to determine when use of a given tool should be discontinued, and a new one substituted therefor. Obviously the skill and of individuals will widely difier, and it not infrequently happens that the use of a valuable diamond is carried so far that its efficiency is impaired, and the stone itself greatly damaged.

It is the object of the present invention to provide means for quickly and accurately determining when a diamond has been so worn that any further use would be marked by decreased efiiciency and also by undue damage to the stone.

To this end, according to the present invention, there is provided a gauge whereby any workman, without the exercise of his individual skill and judgment, can at all times readily determine when the use of a given tool should be discontinued, and the diamond reset.

' The gauge co-operates with the body of the tool in such manner that an edge of the gauge can be passed over'the diamond only when the latter has been worn down to what may be termed the critical point. The inventive idea involved is capable of receving a varig ety of mechanical expressions. Broadly, the gauge and the tool-body are given such relative shapes and dimensions, such as a def initely located shoulder or surface on the one and a definitely located lug or surface on the other, as will enable the gauge to be applie to the tool-body with an edge of the gauge at the proper position for the purpose specified. The accompanying drawings are for the purpose of illustration, but it is to be expressly understood that they are for that purpose only and are not meant to define the limits judgment or GLEN RIDGE, AND CHARLES J. KOEBEL, or WEEHAWKEN,

NEW JERSEY DIAMOND-POINTED TOOLS AND THE LIKE 192% Serial N0. 710,848.

of the invention, reference being bad to the appended claims for this purpose. In the drawings Fig. 1 is an elevation of a tool suitably formed and dimensioned for the gaugesillustrated in other figures;

Fig. 2 is a like View of the same tool with a suitable gauge in position;

Fig. 3 is a modification showing an adjustable gauge; and N Fig. 4 is another modification of the gauge.

In the embodiment of the invention as shown in the drawings, there is the usual cylindrical tool body 1 of metal, with the diamond 2 embedded therein in any wellknown manner so that its operative surface is exposed. The line 33 indicates the point beyond which the diamond should not be worn by use; and when this point has been reached the stone should be reset.

In thepreferred form, a circumferential groove 4-. is cut in thebody 1 in such manner that the shoulder presented by the upper side wall thereof is at a predetermined distance from the point indicated by the line 3 3. The gauge 5, shown in the form of an inverted U, comprises a main body portion with two substantially parallel arms 6 extending therefrom, said arms being so spaced as to permit the passage of the holder 1 therebetween. On the inner face of each of the arms 6 is an inwardly projecting lug 7, these lugs positioning the gauge axially, thatis in the direction of wear, with respect to the tool. In the particular embodiment shown the distance between these lugs cess of the diameter of the holder 1 at the rooved portion; and the width of the lugs is sufliciently less than the width of the groove 4 as to permit the lugs readily to pass through the groove. The distance between the upper edge of the lugs 7 and the top of the opening in the gauge is the same as that bed tween the upper side wall of the groove 4 and the line 3-3. Therefore the line 8 -3 (Fig. 2), which of the opening, in the gauge, is coincident with the line 3-3 (Fig. 1) indicating the limit to which the di mond can e safely worn in use, 1

is slightly in exindicates the upper margin In operation, after the tool has been used to an extent where the workman knows the diamond must have been somewhat worn down, the gauge is applied as shown in Fig.

'2, the lugs 7 in the groove 4. If the diamond,

still pro ects above the line 3-3 it will prevent the passage of the gauge over the tool; if, however, the diamond be worn down to the line 33 the gauge will pass thereover. gln the former case, the workman knows the v .tool is still useful, and an indication of the amount of use left therein will be given by the extent of the projection of the diamond I position the groove in the tool with respect may be to the line 33 of the diamond that the distance between the two will be uniform in all tools. so that a standard gauge may be used with all holders of a like diameter. But, as these gauges may be stamped out very cheaply from sheet metal, the maker may of course have an individual gauge for each tool, if he prefers to dispense with the otherwise requisite uniform distance between the grooveand the line 3-3.

For toolsof a different diameter, gauges 5 provided with any desired spacing between the lugs.

In carrying out the present invention it has been found desirable to have a uniform or standard distanceibetween the circumferential groove in the tool and the line 3-3 of the diamond, and this regardless of the diameter of the tool. When such uniformity of distance is maintained, for tools of varying diameters an adjustable gauge such as shown in Fig. 3 ma be used. This gauge comprises the two mem ers 8 and 9, each havin a d0,wnwa-rdly extending arm 10 with an inwardly projecting lug 7. The member 8 has a slot, and the member 9 a hole registering with said slot; a binding screw 11 passes through these two openings, and holds theparts securely when positioned with the desired space be tween the lugs.

A-modification of the invention is shown in Fig. 4, where merely a small recess 12 is made in the side of the holder 1, instead of the circumferentialy groove heretofore described. A

in conjunction with such a holder, the lug fitting into the said recess in the holder. But sucha gauge has to be used with some degree of care by the workman, as it is liable to be tilted to the right or the left, and thusfail age of wear has been reached, that gauge comprising an L-shaped .member 5, and having but one lug 7 is used to give the accurate information obtainable from the use of the U-shaped gauge.

Having thus describedthe invention, the

following is claimed:

1. A gauge to be used with a diamondpointed tool or the like for testing the relation of the point proper of the diamond to the body of the tool, the latter having shoulders at opposite sides thereof and at right angles to its axis, said gauge comprising a body portion having two arms extending therefrom in the same direction and spaced to permit the passage of the tool therebetween, said arms havin on their adjacent faces lugs with shoulders for engagement with the corresponding shoulders on the tool, the dimensions of the gauge being such that, when its shoulders are engaged with those of the tool, the inner edge of the gauge body may be passed over the diamond only after the latter has been worn down to a predetermined extent.

2. A tool holder carrying a cutting-jewel and having a shoulder located afixed distance from the critical point beyond which the jewel should not be worn down in use, whereby a gauge which measures said distance may be positioned against the shoulder and along the holder to a point adjacent the jewel to indicate when the jewel is worn down to the limit of desirable wear.

In testimony whereof, we names to this specification.

FRANK E. KOE'BEL. CHARLES J. KOE-BEL.

have signed our ion 

